Project Fireball

April 16th, 2000

Fireballs are surprisingly difficult to make. This was my first attempt:

There is about 1/2 gallon of gasoline behind Bugs Bunny. The yellow box
contained a copy of the Symantec C++ compiler (another story and unrelated to the fireball
attempt). The two half-gallon milk cartons contained the standard mix
of explosives with aluminum foil, steel wool, and aluminum powder in them.
It was anticipated one or more of these metals would burn long and hot enough to
ignite the atomized gasoline. The 1 quart container had smokeless gun
powder in it.

The result of the detonation is below:

As a fireball, it was a complete failure.

December 2001

Ry Jones and I tested a number of different substances to help with the
ignition of the gasoline. Basically we needed something would ignite
during the detonation and continue burning long enough for the gasoline to mix
with the air in the proper ratio such that the gasoline will ignite and
propagate. First we tried a Titanium "powder". It is more
like a collection of flakes of various sizes. It varied roughly from -20
to 200 mesh. We put about a tablespoon of it in on top of a pint (about 1
pound) of explosive and put a gallon of gasoline on top it.

For scale, note the 30 gallon barrel off to the right of the
picture to the upper right of the 'M' in 'PM'.

Thermite made a nice flash, but no fireball. Click on the picture for the
video.

Aluminum foil without the gasoline to try and duplicate the flash.
Click on the picture for the video.

Without gasoline or other additions to the explosives. Click on the
picture for the video.

Notice the explosive by itself sometime generates a small flash, but the
addition of the aluminum foil it makes a fairly large flash.

Next we duplicate the success with the titanium powder.

Titanium powder seems to be a winner. Click on the picture for the
video.

December 12, 2002

Ry and I again did some experiments. We used two pounds of explosives
and put the titanium powder in various locations with the gasoline behind the
explosives. Click on the pictures below for the video (you may need to
install this codec).

January 19th, 2003

Wanting to get a high resolution picture of a fireball I took my daughter Kim
and her cousin Lacey out for some tests. Kim ran the rifle, the video
camera was on a tripod, and I had the still camera. Lacey provided the
additional sound effects.

The picture above was taken in daylight with some cloud cover. The light
from the fire was so bright that it made the ground appear dark as the camera
adjusted for the intensity. This used four gallons of gasoline (one gallon
behind, one on each side and one on top) and four pounds of explosives. The shooter, daughter Kim, was about 100 feet away and
was accompanied by her cousin Lacey (HOLY SHIT!) in the "giggle
fit" after the fireball goes up.

Just as the fireball disappears out of sight you will hear some "happy
sounds" from some other shooters. These guys came over as we were
mixing up the next batch and said, "You're Joe, aren't you?".
<heavy sigh> My reputation precedes me.

Here is what Kim and Lacey wrote about their experience.

A wild heat
engulfs my body
then grips my heart

My body is warmed
all the way through
my fingers to my feet

I'm not scared
for there is no pain
Just an immense heat

Kim Huffman-Scott

"Safety’s off" Kim replied as she took aim and fired. "Baawoooo!" screamed
the fire as both Joe and I were engulfed with the radiant illumination. It looked for just a moment as if the fiery gates of hell had suddenly opened
for the world to see. In that split second it seemed to me that the earth had opened to reveal itself from within. From a hundred feet away my face
and hands tingled as if I had walked into a warm room. I wanted to run in fear
but I was mesmerized by the sight of such power and the only outlet of emotion that I was capable of was a few profanities. The ball of fire
swelled high into the air where it turned into a puff of black smoke. A small fire continued to burn up though the rocks marking the initial spot of
ignition. Kim proudly rose from the ground with a look of utter satisfaction. The three of us laughed with excitement as we decided to try
it one more time.

Lacey Swanson

April 19, 2003

We tried using diesel instead of gasoline but it didn't
ignite. It has a lower ignition point but it doesn't vaporize nearly as
easily. Liquids don't burn, vapors do. The second and third shots are
using 'farm gas'. No road tax is paid on it so I can get it cheaper.
I was concerned because we don't believe it has any ethanol in it but now we
know it will work (at least some of the time) when the weather is warm.
The temperature for today's test was about 60 F, plus the gas was in plastic
containers sitting in the sun for many hours.

Conclusion

We now have a recipe that almost always works. Occasionally we have
unexplained failures to ignite. We are beginning to suspect that in cold
weather we have better luck when we use gasoline that contains ethanol. In
addition to the cold weather characteristics of gasoline with ethanol, it will
ignite when the fuel concentration in the air is between 3.3 and 19%.
Straight gasoline has a much narrower range of 1.2% to 7.6%. There is also
data to indicate that we just need to use more titanium powder.